LSI technology used for multimedia devices has been developed to increase the speed and amount of data that is transferred. Technology for mounting LSI chips on an electronic device with high density has been developed accordingly.
Various structures have been proposed for packages (semiconductor devices) that are applicable to high density mounting. For example, a ball grid array (BGA) package arranges ball terminals instead of lead terminals in a grid array on the surface of the package. Japanese Laid-Open Patent Publication No. 2007-149920 describes a tape ball grid array (TBGA) package that uses a tape-like substrate formed by a polyimide film or the like on a package base to increase the capacity and the number of pins.
FIG. 13 describes one example of a TBGA type semiconductor device in a related art. As illustrated in FIG. 13, a semiconductor device 100 includes a wiring substrate 110, a semiconductor element 120 mounted on the wiring substrate 110, an encapsulating resin 130 that encapsulates the semiconductor element 120 and the like, and solder balls.
The wiring substrate 110 includes a tape substrate 111 and an adhesive layer 112 formed on one side of the tape substrate 111. A wiring pattern 113 and bonding pads 114 are formed on the adhesive layer 112. Further, a solder resist layer 115 covering the wiring pattern 113 is formed on the adhesive layer 112. An adhesive agent (not illustrated) adheres the semiconductor element 120 to the solder resist layer 115. The semiconductor element 120 includes electrode pads 120P connected to bonding wires 122, which are electrically connected to the bonding pads 114. The encapsulating resin 130 is formed on the adhesive layer 112 to encapsulate the semiconductor element 120, the bonding wires 122, and the bonding pads 114.
A plurality of through holes 112X extend through the tape substrate 111 and the adhesive layer 112 at given locations. The solder balls 140, which are electrically connected to the wiring pattern 113, are arranged in the through holes.